基于聚类分析的微博用户标签自动生成

基于用户发表的微博内容进行标签的自动生成,主要研究的是基于聚类分析的用户标签自动生成.本文首先介绍用到的关键技术:聚类技术和TextTank,提出了Baseline系统,接下来详细说明了基于聚类分析的标签自动生成方法,最后通过实验对该方法进行了分析和评价.实验结果表明,该方法生成的用户标签能够有效地解决同义标签的堆积问题,使得生成的标签能够在更多的维度上体现用户的兴趣.     

OCDMA系统中新型正交码的设计及性能研究

为了得到性能较为良好的正交码,采用没有重复数字的全间隔集,进行了地址码的设计和系统仿真验证,设计出的正交码具有理想的相关性和灵活的码字容量。分析整个系统,在考虑各种噪声和多址干扰的影响下,推导出正交码的误比特率公式。自行设计并搭建了采用光纤延时线作为编解码器的异步光码多分址系统。结果表明,该正交码能够适应更多用户的需求,通过误比特率公式计算和系统仿真得到的结果都较为理想,此研究对需要大容量的光码多分址系统的进一步发展具有一定的帮助。     

Study on Characteristics of Various RF Transmission Line Structures on PES Substrate for Application to Flexible MMIC

In this work, the coplanar waveguide is fabricated on a PES (poly[ether sulfone]) substrate for application to a flexible monolithic microwave integrated circuit, and its RF characteristics were thoroughly investigated. The quality factor of the coplanar waveguide on PES is 40.3 at a resonance frequency of 46.7 GHz. A fishbone‐type transmission line (FTTL) structure is also fabricated on the PES substrate, and its RF characteristics are investigated. The wavelength of the FTTL on PES is 5.11 mm at 20 GHz, which is 55% of the conventional coplanar waveguide on PES. Using the FTTL, an impedance transformer is fabricated on PES. The size of the impedance transformer is 0.318 mm × 0.318 mm, which is 69.2% of the size of the transformer fabricated by the conventional coplanar waveguide on PES. The impedance transformer showed return loss values better than –12.9 dB from 5 GHz to 50 GHz and an insertion loss better than –1.13 dB in the same frequency range.     

Demonstration and field trial of a resilient hybrid NG-PON test-bed

A multi-layer next generation PON prototype has been built and tested, to show the feasibility of extended hybrid DWDM/TDM-XGPON FTTH networks with resilient optically-integrated ring-trees architecture, supporting broadband multimedia services. It constitutes a transparent common platform for the coexistence of multiple operators sharing the optical infrastructure of the central metro ring, passively combining the access and the metropolitan network sections. It features 32 wavelength connections at 10 Gbps, up to 1000 users distributed in 16 independent resilient sub-PONs over 100 km. This paper summarizes the network operation, demonstration and field trial results.     

Simultaneous Prediction for Multiple Key Performance Indicators in Semiconductor Wafer Fabrication

The prediction and key factors identification for lot Cycle time (CT) and Equipment utilization (EU) which remain the Key performance indicators (KPI)are vital for multi-objective optimization in semiconductor manufacturing industry.This paper proposes a prediction methodology which predicts CT and EU simultaneously and identifies their key factors.Bayesian neural network (BNN) is used to establish the simultaneous prediction model for Multiple key performance indicators (MKPI),and Bayes theorem is key solution in model complexity controlling.The closed-loop structure is built to keep the stability of MKPI prediction model and the weight analysis method is the basis of identifying the key factors for CT and EU.Compared with Artificial neural network (ANN)and Selective naive Bayesian classifier (SNBC),the simulation results of the prediction method of BNN are proved to be more feasible and effective.The prediction accuracy of BNN has been obviously improved than ANN and SNBC.     

全业务经营下的接入光缆演进方案研究

随着全业务运营的竞争,移动运营商已开始向全业务经营转型,在满足全业务发展的过程中,接入层光缆网络资源是否充足以及结构是否合理已成为重要因素。文章在全面分析了全业务经营各类型业务的接入光缆需求后,探讨研究了全业务经营下本地接入光缆网的演进方案及业务承载方式。     

基于PXI总线的自动测试系统设计

针对电子设备的测试需求、系统开放性和可扩展的要求,开发了一种基于PXI总线的自动测试系统。详细说明了此系统的硬件构成和软件设计方法。该系统以PXI内嵌主控计算机为核心,以LabVIEW软件为开发环境,并综合运用标准接口和总线技术来实现系统的综合设计。系统具有良好的人机交互界面,在使用过程中运行稳定可靠、测试效率高、使用维护方便。     

W波段VLASOV准光模式变换器的优化仿真

针对传统天线受到高功率微波的输出功率和脉宽限制的问题,对W波段准光模式变换器进行优化仿真。基于准光近似理论,建立了输入模式为TE03模、频率为94 GHz的阶梯型VLASOV准光模式变换器模型,并进行了仿真优化设计,得到了优化后的VLASOV准光模式变换器数模型参数。仿真结果表明：辐射波束具有明显的方向性,波束明显变窄锐化,主瓣增益很高,达到29.46 dBi,能量主要集中在主瓣上,旁瓣增益较低,辐射效率达到87.36%。     

BST薄膜高介电调谐率和低介电损耗的设计

钛酸锶钡(BST)薄膜显著的介电非线性效应归因于Ti4+偏离氧八面体中心的位移。从BST薄膜的相变行为出发,讨论影响介电性的3种因素,即组分、电极材料和薄膜厚度,以期保持BST薄膜高介电调谐率的同时,获得低介电损耗,为最大限度地提高BST微波移相器的性能提供可能。